Military personnel, firefighters, law enforcement officers and other professionals working in hazardous environment are commonly exposed to fire hazards. In order to reduce fire and flame related injuries, protective clothing is desired for such user community. Conventional protective clothing is designed to protect the wearer from hazardous environmental exposures such as flash fire, high heat, radiation, chemical and biological agents and body fluids. Depending on the severity of hazardous exposure, protective clothing differs in the degree of protection. In firefighting, maximum protection against flame and heat exposure is typically provided by using thick insulative layers of inherently flame retardant aramid fabrics, typically such as materials sold under the trade names KEVLAR® fiber and NOMEX® fiber (E.I. du Pont de Nemours and Company), and fluid barrier properties are provided by using microporous membrane, typically such as materials sold under the trade name CROSSTECH® moisture barrier (W.L.Gore & Associates). For professionals in hazardous environments where short duration exposure to fire or explosions is possible, such as military, search and rescue, police, etc., egress from fire is the protocol, so protection requirements are less stringent than for firefighters. The goal for protective gear in these circumstances is to provide some enhanced protection to allow the wearer to get away from the hazard quickly and safely, rather than to combat the hazard. It is believed that protection from flame exposure requires clothing which is resistant to or does not ignite, melt or disintegrate or break open upon short exposure to such hazards.
Traditionally, flame resistant protective garments have been made with an outermost layer comprising non-combustible, non-melting fabric made of typically KEVLAR® fiber, NOMEX® fiber, PBI type fibers, etc. These fibers are inherently flame resistant but have several limitations. Specifically, these fibers are very expensive, difficult to dye and print, less abrasion resistant and offer unsatisfactory tactile comfort as compared to nylon or polyester based fabrics.
For optimum user performance in many hazardous environments, protective gear should be not only flame resistant, but also waterproof and comfortable. Wearers prefer lightweight, breathable, waterproof and comfortable protective clothing. Conventional waterproof and breathable garments are made from monolithic or microporous film(s) bonded to a fabric surface by coating or lamination process. Adhesive lamination is a commonly used technique to join substrates together and it is widely used to bond fabric to film, film to film and/or combinations thereof. Adhesive layers applied during lamination may be continuous or discontinuous, depending on the nature of the adhesive; coatings are typically continuous layers applied during the coating process.
The cost of waterproof, flame resistant, protective clothing has been an important consideration for the large number of hazardous exposure applications outside fire protection, thereby precluding the use of typical, inherently flame resistant textiles such as those used in fire fighting community. Coatings have been used to create products with resistance to flame. These products typically use a continuous thick coating or layer of flame retardant polymer over a non-flame resistant fabric surface, such as nylon, polyester, and the like. In addition to flammability, these non-flame resistant textile fibers typical melt in the presence of high heat or flame. However, molten textile fibers present an additional danger in that skin contact can cause severe burns. In attempts to minimize these risks, textile producers have moved towards very heavy flame resistant coatings on such meltable, combustible textiles. For example, mattress fire barriers are typically made using a thick, flame retardant polymer coating on a non-refractory textile substrate. Additives such as halogenated flame retardants, metal hydroxides, phosphorus compounds and intumescent materials or combinations thereof have been used to make these polymer coatings flame retardant. US 2005/0287894, for example, discloses such a coated flame retardant product that utilizes a thick polymer coating to impart flame retardant properties to fabrics which are inherently not flame retardant such as nylon, polyester and cotton. The heavy coating of flame retardant polymer makes such coated products heavy, non-breathable, stiff, and generally unsuitable for protective clothing applications.
Overcoming the limitations of heavily coated, non-breathable, meltable flame retardant materials is difficult. In order to improve breathability and to reduce weight for garment applications, flame resistant laminates of inherently flame resistant textiles such as NOMEX® fabric are typically used. Laminates used in flame resistant breathable garments are typically constructed by joining together inherently flame retardant fabric and lightweight breathable films. CROSSTECH® moisture barrier, noted earlier, is an example of such a flame resistant laminate. The flame resistant NOMEX® fabric is oriented to be the outermost layer for flame protection. As previously mentioned, the use of an inherently flame resistant outer textile significantly increases the cost of such flame resistant protective apparel.
Accordingly, a long-felt need has existed for laminates and resulting garments, as well as other protective gear made from these laminates, for workers in hazardous environments which are breathable, waterproof and flame resistant, yet have additional advantages such as being lightweight, comfortable to wear, flexible, easy to color, fast drying, and affordable, which features do not exist in conventional flame resistant laminates and garments.